The Lizard Log

The Langkilde Lab in Action

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Testing the environmental matching hypothesis – return to Alabama!

Another summer field season has now come and gone! This summer I returned to Solon Dixon Forestry Education Center in Alabama (one of my favourite spots on earth!) to continue my research on how stress during gestation influences the offspring of eastern fence lizards (Sceloporus undulatus).

Last year, we investigated how physiological stress during gestation (at the level of a non-lethal predator encounter – for example, when a lizard encounters a couple of toxic fire ants, but isn’t killed by the ants) affects survival of mothers, and how many of their eggs successfully hatch. You can read more about this experiment, and the fieldwork that went into it, here (and stay posted for the published results soon!).

This year I wanted to build on these results and ideas to test how maternal stress influences the offspring that do hatch and make it out into the world. Do they themselves then cope better with a stressful environment, having been “primed” for it by their mothers (the “environmental matching” hypothesis)? Or are offspring born to stressed mothers poorer in quality, and less likely to survive in the wild, regardless of how stressful their environment is? In order to test these ideas, we first made the long trip south to collect gravid females from south Alabama early in the summer, and to build experimental enclosures in which to eventually release their offspring. I then repeated the maternal stress treatment from last year and once again became a lizard mama as I followed the females from laying their eggs, to incubating the eggs, and eventually seeing these bite-sized babies hatch out!


Freshly hatched fence lizards – <1g!

Once they hatched, the offspring went into the enclosures that we’d built. These enclosures were designed to test whether maternal stress programs offspring to be able to better deal with a stressful environment. The enclosures either contained a key stressor (invasive fire ants), or were fire ant-free. Each day I conducted a mini-census, walking through enclosures to look for each lizard – as you can see in the video below, babies were marked so I could tell exactly who was present each day (and so, which lizards survived, and which didn’t). I also observed their behaviour, and how they used the habitat available to them (for example, did offspring from stressed/non-stressed mothers differ in whether they liked to be out in the open, like the lizards you see in the video – or did they hide more?).

After a great summer (if measuring 200+ baby lizards isn’t a metric of a great summer, I don’t know what is), I’m now back at Penn State with a box of data to work through. I’m excited to report back on what I found in the coming months – so stay tuned!




Hanging out with an adult female Sceloporus at Solon Dixon


Beautiful Solon Dixon


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Solon Dixon!

Hey everyone!

Even though I am continuing the same project from last year (how maternal stress affects the offspring in fence lizards), there are still some striking differences. One of the biggest is that there are fellow grad students and a post doc this summer!


From left to right: Cameron (PhD), myself (PhD), Kirsty (post-doc), and Dustin (PhD).

Also, last year we made the drive in one day, however this year we broke the drive up over 2 days. This gave us an excellent opportunity to experience different parts of the USA on our drive. For the night we stopped in Knoxville, TN and had dinner at an amazing place called Calhoun’s On The River. True to its namesake, it had a beautiful view of the Tennessee River!


After all the driving, we finally made it back to Solon Dixon and started catching lizards. As usual, the lizards’ personalities were very evident.


Male fence lizard unamused with our attempts to catch him


Apparently the female lizards found that corner of the tub to be very interesting.


As I went to put this female back in her tub, she refused to let go of my fingers!

On top of finding many fence lizards, we were also about to see many other reptiles and amphibians!


A barking tree frog tightly hugging my finger.


An American alligator, at a very reasonable size to handle.


A yellow bellied slider who found a little bit of water to sit in.

eastern glass lizard

A glass lizard!

As I spend more time down here, I find it rubbing off on me more and more.


Very tempted to get a cowboy hat.

After catching the females, our first trip came to an end. However, we were quickly back down to release the females and run experiments with the hatchlings. With us this time we had an undergraduate researcher, Jen!


The Bayfront Park, overlooking Mobile Bay. Located right next to one of our field sites, Blakeley State Park.

As we wait for more hatchlings to emerge, we have been focusing on removing fire ants from some of the enclosures we built. As fire ants are highest in the mounds earlier in the day, this means some early mornings. On the up side, it also means we always get to see the sunrise.


Sunrise right near the enclosures.

Most things have gone well, with only one piece of equipment starting to show signs of wear, but this just gave me an excuse to do some handywork!


Used some steel epoxy to seal a leak in the pot we boil water in for fire ants.

Things have started to pick up in terms of hatchling, so soon you should be able to hear about how things are going with them. Until then, here is a pic from right here at Solon Dixon


With the drier weather they are finally able to do prescribed burns.



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Sweet Home Alabama

This summer marks the 10 year anniversary of working on the fence lizard / fire ant system. And I got to spend it at the Solon Dixon Forestry Education Center. It was like coming home. I used to spend 3-4 months a year there but haven’t been back since 2011 (a cost of reproduction). And this year I got to share this with my mom and 5 year old.

Me, my mom, and my 5 year old hanging out with a gorgeous indigo snake.

Me, my mom, and my 5 year old hanging out with a gorgeous indigo snake.

Driving down the road that leads to the Solon Dixon Forestry Education Center (and all roads apparently lead to the Center) my heart rate increased, and I couldn’t stop beaming. It was wonderful driving through the longleaf pine forests, an amazing ecosystem that is being restored thanks for the efforts of organizations such as the Longleaf Alliance, and past gorgeous Cyprus swamps. I couldn’t wait to get there.

Longleaf sunset

A longleaf pine forest sunset – the view from behind our dorm.

Solon Dixon was pretty much like I remembered it, but there were a few noticeable changes. They have built a gorgeous new classroom facility – I need to find an excuse to take a class down here to take advantage of it.


Solon Dixon’s fancy new classroom facility.


Auditorium inside the new classroom facility.

And they had to gate off the road to the amazing freshwater spring as some folks were tearing it up looking for sharks teeth (this area used to be under the ocean many eons ago). This is a gorgeous but freezing cold freshwater spring that provides welcome relief on a hot Alabama afternoon.

David doing his best "creature from the black lagoon" impersonation.

David doing his best “Creature from the Black Lagoon” impersonation.


A resident of the spring.

Michaleia getting to know another visitor to the spring.

And since Solon Dixon is only a little over an hour from the gulf coast, we had to take a trip to play in the gorgeous white sands, and sample some of the best ice cream in the south!

Loving the white sand beaches!

Loving the white sand beaches!

Henderson Beach State Park

Henderson Beach State Park

Amazing frozen custard! And the chance to become a hotdog for a few minutes.

Amazing frozen custard! And the chance to become a hotdog for a few minutes.

We share Solon Dixon with the Auburn University forestry and wildlife students. And are fed like kings, including delicious dessert at least twice per day. My first year I blamed the tumble dryers at Solon Dixon for shrinking my clothes until I got home and realized my other clothes had mysteriously shrunk too. Waiting in the lunch line this summer I was met with a photo from years ago when Katie Boronow and I tagged along on a swamp walk with the forestry students. Oh sweet memories…

A photo from 8 years ago. That’s me in the yellow, front left.

Amongst all this fun, there was work to be done. I helped get David going with his project on maternal stress. And collected blood samples and information on badge coloration of female lizards for a project Braulio will be doing to see whether “bearded ladies” are suped up on testosterone. While we were stalking a large female one afternoon, we heard a huge rustle in the leaf litter. We quickly figured out it was not in fact a bear, but instead two males engaged in battle. They moved onto the railroad ties, and Michaleia caught some of the action on video:

We didn’t get the lady… hopefully the males had better luck.


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Stress and Fence Lizards

Through the lens of conservation, I became interested in stress. My biggest interest is in how humans can cause stress in animals, and how that stress impacts them. To this end, I started studying the effects of stress within an individual. I looked at how stress changed different hormones and metabolites in adult male northern elephant seals, and how that response differed during different times of the year.


Adult male northern elephant seal (Mirounga angustirostris), about 1,500kg, asleep

This experience was great and fueled my excitement and curiosity about studying stress. I started talking with 2 professors at Penn State (Drs. Sheriff and Langkilde) about what they were looking into and fell in love with the project I am working on now. Instead of studying stress within an individual (stress the animal, see what happens to them), we are going to look at the effects of maternal stress (stress the mother, see what happens to their offspring). The other large difference was instead of being in California working on seals, I was going to be in Alabama working on eastern fence lizards!


A female fence lizard (L), the ones I am studying, and a male (R).

Even more striking then their back color is the color of their underside!


The dark blue chest and neck of a male eastern fence lizard.

I had never been to Alabama or worked with herps before, but I was incredibly excited. Last summer I was able to go down with Chris Thawley and he showed me where to look, how to catch the fence lizards, and many other things. That time, combined with Tracy, Gail, and his answering of my constant questions throughout the year (thank you so much!) helped alleviate some of my own stress about the field work.

So I had a plan laid out. I would get gravid female lizards from the field and have 1/2 be stressed, 1/2 not stressed. I would then take them back to the lab and have them lay their eggs, and then look at differences in the offspring. I thought that sounded pretty simple, but lizards prove to be an elusive bunch. So far we have all the females we need from Conecuh National forest, but we are being thwarted by the lizards in Geneva State Forest and Blakeley State Park. Luckily, I have 2 skilled field techs working with me, Michaleia and Miranda.


Michaleia drying a colored mark on the back of a lizard (L), and Miranda out in the field (R).

They have been a tremendous help in not only finding the lizards, but also collecting data and samples as well as catching the lizards. We have been learning so much about the area, the wildlife, and how to handle the lizards. The lack of lizards from Geneva and Blakeley has not curbed my enthusiasm about studying this amazing lizards, and I am looking forward to working with them more and getting into the meat of my research with them.


P.S. Here are some other interesting things we have been seeing down here.


Fire ants eating the tail of a fence lizard

And some other herps!


A gray rat snake, Pantherophis spiloides, blending into the leaf litter.


A southern toad, Anaxyrus terrestris, hanging out.


A ground skink, Scincella lateralis, found at our field station.


A green anole, Anolis carolinensis, perched on the side of a log.


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Everybody Likes Pretty Pictures

Since our research trips to the South consist of only one short excursion this summer (we need to publish all the data we have rather than running every awesome experiment we can think of!), I took a quick one week jaunt through Alabama and Georgia for some R&R. Whether walking the banks of the Chattahoochee or exploring trails along Mobile Bay, sampling homemade cheese at an out-of-the-way farm or eating some of the best fried chicken and corn nuggets I’ve ever had, I always found some time to catch and grab a few pics of some herps! I’ve posted a selection below to tide you over until the real research starts in a month or so:


This male fence lizard (Sceloporus undulatus) was not happy with me for intruding on his territory along a trail and puffed himself up in the hopes of intimidating me into leaving the area.


We often find fence lizards with ectoparasites like mites and ticks. How many can you spot on this lizard? (Answer at the bottom of this post).


Rounding a bend in the road at 55 mph, I spotted this corn snake (Pantherophis guttatus) in the middle of my lane and quickly straddled him with my car before pulling over on the shoulder. After running back down the road on my own two feet, I snatched him for a quick pic before releasing him into the forest safely off to the side.


I found this ground skink (Scincella lateralis) out foraging in the middle of the day at Kolomoki Mounds State Park in Georgia.


Kolomoki Mounds was also awash in southeastern slimy salamanders (Plethodon grobmani), one of the prettiest slimy salamanders due to their extensive patterning.


This rough green snake (Opheodrys aestivus) appeared rather happy (well, they always look like they’re smiling) to meet me on a trail in Bon Secour NWR.


I chanced upon this kingsnake (Lampropeltis getula) basking quietly in a half log and getting ready to shed.


Six-lined racerunners (Aspidocelis sexlineata) don’t often sit still take have their pictures taken, but this one was a little more tractable than most so I snapped a quick portrait.


For the sharp-eyed among you, there are >3 ectoparasites on this lizard. Mites and ticks tend to concentrate on places where they can get underneath or between a lizard’s scales to attach and feed; these place include areas around the eyes, ears, and pockets of skin on the neck (not very visible here). On just one side, this lizard has a swollen tick in his ear, a new tick on the front of his eye orbit, and a cluster of bright red mites on his upper eyelid. Life ain’t always easy when you’re a fence lizard.

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Spring Break Herpin’

While on a quick Spring Break trip, I needed to get a herp fix since I’ve been stranded in a land of ice and snow (errr, State College) for the past four months. Alabama to the rescue. While I mostly just hiked in the glorious (to me) 65-70 degree weather (and did manage to actually get a sunburn on my pasty white arms), I did see some herps along the way, whether by flipping a random rock and log or just stumbling across the odd lizard. Here are some quick pics to tide you over the next month or two until spring unleashes warm enough weather for the herps to come out in force a little farther north.


My first fence lizard of the year! This lady was quite cold but basking at the base of a tree trying to get a jump on her activity season.

After quickly catching the fence lizard (hands a real lizard ninja does it!) I contemplate just how the heck I'll set up my projects this summer.

After quickly catching the fence lizard (hands only…how a real lizard ninja does it!) I contemplate just how the heck I’ll set up my projects this summer.

Fire ants were still active as well, although they needed a little motivation (errr, an attacking stick) to get them to show themselves in the cooler weather.

Fire ants were still active as well, although they needed a little motivation (errr, an attacking stick) to get them to show themselves in the cooler weather.

A seal salamander (Desmognathus monticola) works on its tan streamside in the mountains of northern Georgia.

A seal salamander (Desmognathus monticola) works on its tan streamside in the mountains of northern Georgia.

Another desmog takes a peek out of the stream to cast a wary eye at the bumbling human who just pulled a rock away from it's burrow mouth (I put the rock safely back).

Another desmog takes a peek out of the stream to cast a wary eye at the bumbling human who just pulled a rock away from its burrow mouth (I put the rock safely back).

A marbled salamander (Ambystoma opacum) squints its eyes in the bright light after being found underneath a log in southern Alabama.

A marbled salamander (Ambystoma opacum) squints its eyes in the bright light after being found underneath a log in southern Alabama.

Welp, that’s all for now! Hopefully a panoply of critters will be out here in PA soon enough, and we’ll be rolling in fence lizards (and hopefully not fire ants!) in the near future.

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Alabama Adventures

Hi, my name is Jennie. I’m an intern, on loan to the lab through Northeastern University’s co-op program. I spent March through May working at Penn State, assisting with a variety of projects in progress and conducting some independent research with Tracy’s guidance and support. I then tagged along on the lab’s second field excursion this past summer season, and I worked with a subset of the Langkilde cohort at the Solon Dixon Center in Alabama. Though much of my time was spent assisting with projects of the lab team , my personal research involved conducting experiments using Gastrophryne carolinensis, the Eastern Narrow-mouthed Toad, (which is actually an unusual type of frog, in the family Microhylidae).


An Eastern narrow-mouthed toad in all its glory

These little guys are fossorial, burrowing about pointy face first under logs and other cover. The summer is their reproductive season, when they can also be found in or around water by the males’ charming call – a high-pitched “waaaaaaaaaah” reminiscent of a sheep in distress or a cellphone vibrating on a countertop. They are ant specialists, with resilient, slimy skin and a protective turtle-neck like fold above the head to defend them from their prey. It has also been suggested that the gooey coating Gastrophryne secrete may contain defensive compound(s); one hypothesis suggests that these compounds originate from the venoms or toxins in the ants that they eat which may then be sequestered by the frogs.

G. carolinensis showing the distinctive skin fold on the neck which may protect them from attack by ants, their preferred prey

G. carolinensis showing the distinctive skin fold on the neck which may protect them from attack by ants, their preferred prey

G. carolinensis are a species of interest for the Langkilde Lab because their range overlaps with areas invaded by fire ants. In addition to displacing other species of ants which Gastrophryne typically eat, fire ants might impact the survival of individuals. It is clear that fire ants can damage Gastrophryne despite their specialized skin (they often have visible lesions after stings), but these frogs appear to be doing pretty well in invaded areas, as evidenced by their abundant calling, despite feeding on fire ants.

To examine whether the goo secreted by Gastrophryne might be an effective deterrent to fire ants, I designed the following experiment:

1)      Catch a bunch of Gastrophryne.  This necessitated extended, rapid log flipping in broiling heat and wading into flooded roadside ditches – 1 million thanks to Sean, Chris, and both Marks for their invaluable help!

2)      Put out yummy baits to attract fire ants, see previous post.

3)      Place a swab adjacent to the bait. I am comparing 4 types of swabs, rubbed thoroughly on one of the following: a Gastrophryne, a hotdog (which should attract the ants as a food source), some water (as a control) or a Hyla chrysoscelis, the Cope’s gray tree frog which definitely secretes something unpleasant (as do many amphibians; independently confirmed for these guys by the persistent burning sensation in my Smilax wounds after handling them).


A Cope’s Grey Treefrog (Hyla chrysocelis). Photo credit: B. Carlson


Me prepping for a fire ant trial by swabbing a narrowmouth toad.

4)      After 30 seconds, swiftly reclaim the swab and count the number of fire ants on it.

5)      After repeating 3) and 4) ad infinitum, collect the bait and pop it in the freezer to allowing counting of the foraging ants, so variation caused by the number of ants present can be accounted for.

I’m starting to process the data from this experiment, but I expect that: 1) the swabs with hotdog residue should have the most fire ants on them, and 2) if the secretions of the narrowmouth toads and treefrogs are indeed noxious to fire ants, that those swabs should have the fewest fire ants on them. We’ll see how the data analysis works out!

As is generally the case when implementing a new experimental procedure, I shortly encountered an unforeseen complication – Gastrophryne get pretty dried out after being swabbed multiple mornings in a row.  Additionally, when given time to regenerate their goo in captivity on a diet of termites, they preliminarily appear to be more attractive to the ants. Interesting! Maybe in future experiments we can examine how diet influences the noxiousness of Gastrophryne goo!

A second experiment I attempted was to evaluate feeding preferences of Gastrophryne for different species of native ants and fire ants collected around the Dixon Center. I was hoping the Gastrophryne would actively hunt when presented with a bevy of ants, so I could see if they preferred a particular species.  However, when placed in their novel Gladware environments they seemed too distracted to do anything but attempt escape or tuck into a corner…Poor little buddies! I got to see them zap any ants that blundered into their vicinity though; that was pretty neat.

On this summer’s trip, I was able to do all kinds of cool field biology, have a lot of fun, and learn constantly (being beleagueringly uninformed compared to my herpetologist compatriots, whose patience with my inexperience is greatly appreciated!) – Thanks to the Langkilde Lab for providing me with such an awesome opportunity!